Here's another vote for the Glock. The only issue you might experience is limp wristing. If your wife is small or has little upper body strength she might not grip the Glock steadily enough for it to function reliably. This is about the only way to make a Glock malfunction. (They do often fail to lock the slide open after you fire the last round).
They require little maintenance, but don't feel as good in the hand as other designs.
My recommendation for someone wanted a "general handgun" is always the Glock 19 (with night sights).
My recommendation for someone wanting a "to hades and back" handgun in a superior fighting cartridge is the HK USP. This will, however, be too large for your wife's hands. Its big in my hands, but they are STONE reliable. Just don't shoot cast bullets because they have polygonal rifling.